Stabilizing means for electric-arc furnaces.



O. E. GUYE.

STABILIZING MEANS FOR ELECTRIC ARC FURNACES.

APPLIGATlQN FILED JANA}. 1912.

1,109,830, Patented Sept; 1, 1914.

f I q l wue/wtoz [Mr/w" 669 6 $513 mkvwl Y/KLW,

consumed in the coils with iron.

UNITED sT p s PATENT OFFICE.

CHARLES EUGENE GUYE, 0F GENEVA, SWITZERLAND, ASSIGNOR '10 SOUTHERN POWER COMPANY, OE ,GHARLOTTE, NORTH CAROLINA, A CORPORATION or NEW JERSEY.

Specification of Letters Patent Patented Sept. 1, 1914.

Application filed. January 8, 1912. Serial No. 670,027.

This coil generally comprises an iron core,

usually divided and surrounded by a winding through which the current flows; such is the case particularly with furnaces designed for the production of oxide of nitro gen used in the manufacture of synthetic nitric acid.

The object of this invention is a means of rendering electric arcs stable.

It consists essentially in substituting, for

reaction coils with iron or magnetic cores,

a coil or coils without any iron, consisting of a copper winding, suitably insulated; this copper Winding may be made in any suitable form, as a blade, a strand, a tube, etc., of copper. There may be one or more such coils, according to the electrical arrangements of the circuit in which the arcs to be rendered stable, either connected in series or in parallel, or even in series-parallel. If currents of great intensity are to be used, the coils may be placed in an oil cooling bath, suitably cooled in the usual way; the coil may alsobe made with sufficient spaces between its convolutions to enable the copper to be cooled by a current of air. Practical study of the conditions of operation of these coils without iron has demonstrated that, with equal impedance, they enable a much more perfect stabilization of the arcs to be obtained than where iron is employed for this'purpose; also, when the power used in the arcs amounts to about 50 kilowatts, and the reaction coils are of average size, the coils without iron are much more economical than those with iron their construction is also simpler since the laminated iron cores are eliminated. Finally, when the coils attain average dimensions, the electric energy consumed in the reaction coil without 1ron is materially less than that This .geconomy in energy results, in a large deimportant commercial progress to be ob tained, which increases with the power of the arcs'to t e-rendered stable. In-particular, this advantage is a maximum when the self induction coil giyen the form which gives the maximum self-induction for the minimum weight in copper. It is especially with furnaces using arcs of great develop ment, such as are employed to produce gaseous chemical reactions that these advantages become considerable.- For example, in applying these coils to a large furnace of the Naville, Guys and Guye type, (French Patent No. 350,120, 1894) of a power of 400 to 500 kilowatts, operating under 5500 volts, it has been possible to stabilize with a loss of energy of ten kilowatts, three arcs inseries, the total devel oped length of which was 20 meters.

In the accompanying drawing,-Figure l is a diagrammatic view illustrating an embodiment of my invention. Fig. 2 is a diagram illustrating the hysteresis loss in magnetic material, and the rate of change of magnetic flux in magnetic material, and also in a magnetic circuit having a permeability equal to one.

In Fig. 1 the reference character E designates electrodes across which an arc is maintained. I designates a reaction coil interposed in the circuit, according to my 'invention.

The reason why these coils without iron or magnetic cores give ordinarily better re sults as regards stability may be explaned by the following considerations: Considering first an ordinary reaction coil having an iron core. When the winding is traversed by an alternating current, the cycle of magnet'zation will be represented in Fig. 2', as abcissa, the intensity I of the magnetizing current, as ordinate, the magnetic flux I which flows through the iron core. At'each instant, the electromotive force of self-indue 'on, which is the principal cause of the stab lity of thearc, will be proportional to the speed pf variation of the flux. Thus it will be seen that it is exactly in the phase Where the intensity diminishes to become zero that is to say, in the most dangerous phase for the stability of the are {either on the curves A.()' and A-U) that the average of this variation is least (especially if the iron presents an appreciable coercive force) 011 the ot ier hand, it the self-induction coil Without iron is employed the variation of the in between the same limits of current as in the former case Will be represented by the dotted straight line A @,A, and it will be seen that the speed of variation of the flux and, consequently, the electromotive force of self-induction, will average greater during all the period Which corresponds to the diminution of the intensity oi the current (that is to say, during the period unfavorable to the stability of the ere}. Tie stability of the are will then be considerably augmented by the employment of a coil Without iron, as has been oleinonstrateol shove stated:

What I claim is,

l, The combination with a, circuit conipsing electrodes between Which an electric arc may be produced and an ere-stabilizing coil of copper wire free from iron included in the circuit.

2. The combination with a circuit comprising electrodes between which an electric arc may be produced, and an arc-stabilizing coil of copper Wire free from iron, included in the circuit in series with said electrodes I In testimony whereof I have hereunto set- 'ny hand in presence of two subscribing Witnesses.

CHARLES EUGENE Witnesses L: H. Munroe, F Yemeni experimentally, a s 

